物理学中的全量子化效应与新的探索  

Full quantum effects in physics

作　　者：陈基[1,2] 孙兆茹[1,2] 张千帆[3] 王恩哥[1,2,3] 

机构地区：[1]北京大学量子材料科学中心 [2]北京大学物理学院,北京100871 [3]中国科学院物理研究所,北京100190

出　　处：《物理》2011年第5期321-325,共5页Physics

基　　金：国家自然科学基金(批准号:10974238;91021007)资助项目

摘　　要：在一般的第一性原理计算中,原子核总是被近似成经典粒子.然而,在一些特殊的体系中,原子核的量子效应对体系的物理性质和物理过程有着至关重要的影响.在相关问题的模拟中,考虑了原子核量子效应的全量子化计算,展示了其独有的准确性.目前,路径积分分子动力学是被广泛采用的全量子化计算方法.而第一性原理的路径积分分子动力学不仅保留了第一性原理计算中电子结构和电子基态能量计算的方法,同时还应用费恩曼(Feynman)路径积分原理,得到了包含原子核量子信息的运动方程.张千帆等人应用第一性原理路径积分分子动力学,计算了BaZrO3中氢核的输运情况.结果表明,原子核的量子化对输运中两个不同的子过程有不同程度的影响,它使得有氢氧键断裂的T过程的势垒下降更多,使T过程成为快过程,从而验证了红外光谱实验的结果,同时否定了传统计算给出的T过程是慢过程的结论.Ions are commonly approximated to classical point-like particles in traditional ab initio studies. However, in certain systems, their quantum effects are crucial to the physical properties and physical processes. A full quantum calculation, which includes this quantum effect, shows unique advantages in such systems. Path Integral Molecular Dynamics （PIMD） has become the most widely used full quantum simulation method. Ab initio PIMD keeps the electron structure and ground state energy of ab initio calculations, while the ions move according to a set of equations which contain the nuclear quantum effect. Proton transfer in BaZrO3 has been studied by PIMD. The results show that the nuclear quantum effect has different influences on the two different subprocesses, reducing the barrier of the transfer process more significantly than the reorientation process, which makes the transfer process faster. This agrees with the experimental observations but differs from the results of early ab initio simulations without the full quantum effect, which indicate that the transfer process is rate-limiting.

关 键 词：全量子化 路径积分分子动力学 第一性原理计算 

分 类 号：O413[理学—理论物理]